For the past year and a half or so they've been releasing it for a month or two and then taking it off the market for twice that long. In Salt Lake, when it's available, it's sold everywhere. I actually saw some 20 oz. bottles of Mt. Dew Throwback a couple days ago. Not sure if that's old stock or whether it's an indication that Pepsi is putting Throwback products back into the market.
I think, lately, our governments bull corn subsidies haven't been keeping the price of real sugar as high as They Want It To Be and hence, PepsiCo, has been able to manufacture Throwback for near or below the cost they produce the corn syrup Pepsi at. I think I read something in some business journal that stated Pepsi has had great sales success with it's Throwback line and has signed an ongoing contract with some cane sugar producer in Idaho, indicating that they'll likely continue to release Throwback every so often in the years to come.
I hope they do. I rarely drink soda, but come Throwback season I increase my consumption and it's always sad to see it disappear from the shelves. I also find the whole concept slightly insulting. Just sell us what we want Pepsi. Don't release some awesome product 'for a limited time' and market it as being superior and expect us to buy the corn syrup after the fact. Make the best product you can Pepsi, all the time; don't denigrate your customer base by making them drink 8 months out of the year, what your own company considers to be an inferior product.
/pepsi rant